Bipolar batteries employ either one of two types of bipolar electrodes, i.e., face-to-face or side-by-side. Face-to-face type bipolar electrodes, utilize an electrolyte resistant, impervious, substantially planar conductive septum having a first polarity active material on one face thereof and an opposite polarity active material on the opposite face thereof. The bipolar electrodes are mounted in nonconductive frames and stacked together such that opposite polarity faces of adjacent bipolar electrodes oppose each other across an electrolyte-filled gap which also contains an electrolyte-permeable, dendrite-suppressing separator (e.g., microporous polyethylene, glass mat, microporous PVC, etc.). The frames are typically either clamped or adhesively secured together. One such battery is exemplified by the patent to Poe et al U.S. Pat. No. 3,728,158, assigned to the assignee of the present invention.
It is known for the electrically conductive septum that separates the opposite polarity active materials of the bipolar electrode to comprise either (1) a thin metal plate (e.g., lead in the case of a Pb-acid battery), (2) an electrically conductive polymer, or (3) a nonconductive polymer having a plurality of rivet-like conductors embedded therein for electrically communicating one face of the septum to the other. For a number of reasons, the use of solid metal plates is preferred for long-lived, high power, bipolar batteries. A metal plate septum particularly useful for lead acid batteries is described in copending U.S. patent application Ser. No. 079,030 filed Jun. 21, 1993 and assigned to the assignee of the present invention. Other metal or conductive septums are useful with other types of battery systems (e.g., alkaline batteries) as is well known in the art. Two of the problems associated with the commercialization of face-to-face type bipolar batteries are (1) insuring that the active material remains in contact with the septum throughout the life of the battery, and (2) manufacturing problems associated with the handling, alignment, assembly and reliable sealing of so many individual components to form the finished battery.
It is an object of the present invention to provide a unique bipolar battery packaging arrangement for face-to-face type bipolar batteries which addresses both the aforesaid problems by providing a conductive septum engaged on its perimeter by a nonconductive frame, and having mesa-like lattices which (1) are integral with the frame inboard its periphery, (2) provide a plurality of active-material-retaining-pockets across the faces of the septum, and (3) are designed and constructed to securely nest within spacer frames positioned between adjacent bipolar electrodes. This and other objects and advantages of the present invention will become more readily apparent from the detailed description thereof which follows.